1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * From: @(#)strtoul.c 8.1 (Berkeley) 6/4/93 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/ctype.h> 43 #include <sys/limits.h> 44 45 /* 46 * Convert a string to an unsigned long integer. 47 * 48 * Ignores `locale' stuff. Assumes that the upper and lower case 49 * alphabets and digits are each contiguous. 50 */ 51 unsigned long 52 strtoul(const char *nptr, char **endptr, int base) 53 { 54 const char *s = nptr; 55 unsigned long acc; 56 unsigned char c; 57 unsigned long cutoff; 58 int neg = 0, any, cutlim; 59 60 /* 61 * See strtol for comments as to the logic used. 62 */ 63 do { 64 c = *s++; 65 } while (isspace(c)); 66 if (c == '-') { 67 neg = 1; 68 c = *s++; 69 } else if (c == '+') 70 c = *s++; 71 if ((base == 0 || base == 16) && 72 c == '0' && (*s == 'x' || *s == 'X')) { 73 c = s[1]; 74 s += 2; 75 base = 16; 76 } 77 if (base == 0) 78 base = c == '0' ? 8 : 10; 79 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base; 80 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base; 81 for (acc = 0, any = 0;; c = *s++) { 82 if (!isascii(c)) 83 break; 84 if (isdigit(c)) 85 c -= '0'; 86 else if (isalpha(c)) 87 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 88 else 89 break; 90 if (c >= base) 91 break; 92 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 93 any = -1; 94 else { 95 any = 1; 96 acc *= base; 97 acc += c; 98 } 99 } 100 if (any < 0) { 101 acc = ULONG_MAX; 102 } else if (neg) 103 acc = -acc; 104 if (endptr != NULL) 105 *endptr = __DECONST(char *, any ? s - 1 : nptr); 106 return (acc); 107 } 108